Filament-support.



$ 23M a I Hawaii; 62

H. 'GILMORE. PILAMENI SUPPORT. AP1LIOATIOH 1ILBD JAN. 30, 1911.

1,001,135, Patented Aug. 22,1911.

- ment in ,Filament-Supports, of which the I unequal expansion of the parts dueto heat those employing the metallic filaments now in common use, require a number of sup-' ora.prolongatiornthereof. This anchoring To a ll whom it may concern;

' of Brookline, county of Norfolk, State of smaller sizes of lamp, where thesupports and the filaments are light, this is practi- ;UN.- I E ST T PATENT OFFICE.

I Bowen]: ammonia, orrnooxrmn, MASSACHUSETTS.

Be it known that I, Hownno Grnuonn, a citizen of the United States, and resident Massachusetts, have invented an Improve following description, in connection with the accompanying drawing, is a specification, like characters on the drawings repre senting like parts. i

The object of this invention is to produce an incandescent electric lamp in which the union or connection between the support for the filament and the glass stem is of such'a character as to be maintained without injury toor fracture of the glassduring tlie either in the manufacture or use of the lamp. Incandescent electric lamps, especially ports for the filament. These supports may simply act to hold the filament at difi'erent points in position. or may also serve as con doctors for the electricity from the end of one filament to the end of another filament.

It has been common heretofore to use a metal wire for a support and to secure. it in position by anchoring it in the glass stem,

is usually effected by heating the glass stem to a red heat and forcing the wire support into the molten glass. In the case of cable, but in the larger sizes of commercial lamps, particularly such as are used for outdoor or street lamps, it is found v'cry ditlicult to make a connection of this'sort which will be maintained during the temperature changes which take place in subsequent steps in the manufacture of the lamp and in the use of the lamp. All the cheaper metals, such as iron and copper which are used for this purpose. have a much greater coefficient of expansion than that of glass.

The present invention is based upon the principle of so constructing thefilament support and so connecting it with the glass stem that upon expansiop ofthe parts the, metal of the support will expand away from the glass without cracking or fracturing it,

' the usual manner.

but at;the same time maintaining its posihon ng-connection therewithi' he nature of the invention will morel FILAMENT-SUPPORT.

fully appear from the accompanying descr1ption anddrawings and will be particu- Specification of Letters Patent. Patehfd Aug. 22 I Application filed January 30, 1911. Serial No. 605,383.

In the rawings, Figure l is a perspective view of a' metallic filament incandescent lamp of a size suitable for out-of-doonlighting having the construction of the present invention embodied therein; Fig. 2 is a. side elevation 'of a portion of the prolongation of the glass stem of the lamp 1n.one stage of its manufacture; Fig. 3 is a viewsiinila'r to Fig. 2 in a second stage of manufacture; Fig. 418 a yiew similar .to. Fig. 3 enlarged and showing the filament supports connects ed therewit .Fig.15 is.atop plan of the construction shown in Fig. 4.

Incandescent electric lamps suchas illus trated in Fig. l-are well knownantl coniprise the'glass bulb 1, the'base 2, with its terminals consisting of the disk 3 and the screw-threaded casing 4, and the glass stem 5. In lamps of -this character employing metallic filaments the stem 5 is usually prolonged, as shown in the rod 6,a ndin using the term stem herein it is intended to in:

clude the entire element made of glass and comprising the base portion or stem proper 5 and the rolongation 6.

The lea ing-in-wn'es 7 and 8 are connected to the terminals 3 and 4 and passout through and are embedded in the stem 5in The metallic filament 9 which extends be tween the terminals 7 and 8 comprises. a. number of loops and is, therefore, supported at various points. In the formfshown in the drawings it is formed into three loops.

Each loop. atits middle is supported by a wire s'u port '10. These wire su ports-are not in t e circuit and their sole. notion is simply to hold the loops in position. Therebeing little strain upon 1: em and being formed of light wire and not conducting the current,v they may be secured to the stemin the usual and common way-by heating the stem red hot and forcing the end of the support into the stem. The free ends of each a loop must be sp-connected, however, that the current may flow therethrough from one terminal 7 to the other terminal 8 and,

hence, the supports for the free ends of the loops of the filament must be conductors and, hence, made of comparatively heavy wire, copper being ordinarily used. In such case, the diiiiculties already referred to arise and'here the present invention comes into play andproduces a simple and ellicient construction whereby all these difficulties are eliminated. I

The filament supports are shown in perspective in Fi 1 and enlarged in Figs. 4 and 5, and in the preferred form illustrated each support comprises a piece of sheet metal 11 having at one-end converging jaw members 12 presenting therebetwcen a narrow mouthed opening and forming a jaw. The other end of the support '11 is bent back upon itself, as shown at 13, to inclosc and lock in position the auxiliary supporting member 14 to the ends of which the loops of filament are mechanically and electrically secured.

The sheet metal construction is preferred, because the main supporting members 11 may be cheaply manufactured by punching,

and may be bent to secure and hold firmly the auxiliary member 14, but it is only essential that the supporting member, however formed, shall present at one end an opening or cavity having a comparatively narrow mouth.

parts together a thickened portion in the form of a disk 15 results. To this thickened portion the supporting member is then connected. In the lamp illustratcdthis connection is formed so as to have the plane of.

the sheet metal supporting member 11 lie transversely of or perpendicular to the stem, but this is obviously not essential.

. lVhen, however, it is done, as in the present case, the disk 15 is flattened to present the tabs or projections 16 shown in Fig. 3.

In the next step of the operation, and by means of suitable clamps and devices not necessary to describe, the stem, 6 is supported and the supporting member 11 is supported relatively thereto so that the tab 16 extends into the opening between the jaw members 12, the member 11 lying in a plane transversely to the stem 6.' The glass is then again heated red hot in the vicinity of the tab and when it is red hot the tab 16 is pinched or clamped in the direction of the length of the stem to force the glass into and about the open jaw of the supporting memher. This process is repeated with respect T to each tab and results in the construction supporting member will'expand away from the glass and not into it, thus preventing'injurious fractures or cracks, but this expansion, owing to the shape of the parts, is insuliicient to destroy their positioning engagement.

It. is to be noted that but one form of filament support has been illustrated and descril)e(l,but it is obvious that the only essential feature of'the construction is that this supportshall present-a cavity or opening which shallengage a portion of the glass of the stem by substantially surrounding and inclosing it, so that when expansion takes place the metal of the filament support may expand away from the glass without becoming disconnected therefrom.

Having fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. An incandescent electric lamp comprising a glass stem, 11 filament support having a coefficient of expansion greater than that of the glass stem and presenting a gripping head substantially surrounding and gripping a portion of the stem of said head thus firmly 'securing the filament support in position at all times upon the stem but expanding away from the glass when heated so as not to fracture the glass while remaining engaged therewith.

2. An incandescent electric lamp compris-.

ing a glass stem, a filament support having a coeflicient of expansion greater than that of the glass stem and presenting an 'open jaw, a portion of the glass ste'm extending into said jaw so as to be substantially surrounded and inclosed thereby, the expansion of the parts by heat tending to move the jaw away from the 'inclosed glass. but not. sufficiently to release the parts from positioning engagement.

3. An incandescent electric lamp comprising a glass stem, a sheet metal filament supporting member having at one end converging 'jaw members 'presenting therebctwecn a narrow mouthed opening, a portion nf'the glass stem extending into said opening so as to be substantially surrounded and inclosed by the jaw members, the expansion of the parts by heat. tending to move the -jaw members away from the inelosed glass.

porting member arranged in a plane perpendicular to the stem and having at one l to be substantially surrounded and inelosecl end converging jaw members presenting by the jaw members. the expansion of the therebetween a narrow mouthed opening, a parts by heat tending to move the jaw memportion of the glass stem extending into sairl hers away from the incloserl glass, but not 20 opening so as to be substantially surrounded l sufficiently to release the parts from posiand inclosed by the-jaw members, the expantioning engagement. an auxiliary supportsion of the parts by heat tending to move ing member, ancl means for uniting said supthejaw members away from the inelosed porting members.

glass, but not sufficiently to release the parts from positioning engagement. 7 V

5. An incandescent electric lamp comprising a glass stem, :1 sheet' nietal filament supporting member having at one'end converging jaw members presenting therebetween a narrow mouthed opening, a portion'of the glass stem extending into said opening so as In testimony whereof, I have signed my 25 name to tlns specification, in the presence of two' subscrlbmg witnesses.

HOWARD GILMORE.

Witnesses LEONA CHANDLER,

FREDERICK S. GREENLEAF. 

